Above- and below-ground characteristics were measured and
compared for six sets of paired trembling aspen (Populus tremuloides
Michx.) clones on the Fishlake National Forest in central Utah.
Three self-regenerating clones were compared with three non-regenerating
clones and three pure aspen stands were compared with three mixed
aspen-conifer stands. Regenerating clones had dense understories
of younger aspen stems, which were not present in nonregenerating
clones. Regenerating clones also had greater numbers of roots
and greater total root surface area than nonregenerating clones.
Aboveground biomass and growth of the aspen in mixed stands was
less than that of pure stands. A corresponding difference in
aspen root mass was not apparent, indicating that the decline
of aspen in mixed stands had not yet affected the root system.
Conifer height and basal area growth rates were clearly greater
than those of aspen, suggesting that aspen will eventually disappear
from these forests in the absence of stand-reinitiating disturbances.

Keywords: aspen, Populus tremuloides, clonal
regeneration, succession

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